SIMBAD references

The ellipticity distributions of different types of dwarf galaxies in the Virgo cluster are analysed using the photometrically measured axis ratios of 260 dwarfs published in Paper II (Binggeli & Cameron 1993A&AS...98..297B), and the eye-estimated axis ratios of 800 dwarfs listed in the VCC (Binggeli et al. 1985AJ.....90.1681B). The apparent ellipticity distributions of normal (non-nucleated) dEs, dS0s, late spirals (Sdm - Sms), smooth irregulars (Ims), and clumpy irregulars (BCDs) are not significantly different from each other by a standard Kolmogorov-Smirnov test. Nonetheless, there is a hint that dEs and Ims are rounder (thicker) than either dS0s, late spirals, or BCDs. There is no evidence for a difference between the flattening distributions of nucleated dwarf ellipticals (dE,Ns) and classical (giant) Es. However, the dE,Ns are significantly rounder than any other dwarf type, including the non-nucleated dEs. The lack of a strong correlation between apparent ellipticity and mean surface brightness seems to favor the oblate spheroid for the intrinsic shape of dwarf ellipticals. However, the pure oblate model significantly fails to reproduce the deficit of round (E0) objects observed for non-nucleated dEs and Ims. Perfect agreement with the observed distributions is achieved by making the oblate shapes modestly triaxial. The same feature has recently been found for giant galaxies (e.g. Lambas et al. 1992MNRAS.258..404L).